TODO and Limitations
====================
.. currentmodule:: mock
Contributions, bug reports and comments welcomed!
Feature requests and bug reports are handled on the issue tracker:
* `mock module issue tracker `_
When mocking a class with ``patch``, passing in ``spec=True``, the mock class
has an instance created from the same spec. Should this be the default
behaviour for mocks anyway (mock return values inheriting the spec from their
parent), or should it be controlled by an additional keyword argument
(``inherit``) to the Mock constructor?
Interaction of magic methods with spec, wraps. For example, should spec cause
all methods to be wrapped with mocksignature perhaps? (or another keyword
argument perhaps?)
Should magic method calls (including `__call__`?) be tracked in `method_calls`?
Could take a patch keyword argument and auto-do the patching in the
constructor and unpatch in the destructor. This would be useful in itself, but
violates TOOWTDI and would be unsafe for IronPython (non-deterministic calling
of destructors). Destructors aren't called *anyway* where there are cycles, but
a weak reference with a callback can be used to get round this.
``Mock`` has several attributes. This makes it unsuitable for mocking objects
that use these attribute names. A way round this would be to provide ``start``
and ``stop`` (or similar) methods that *hide* these attributes when needed.
(`_name` is a mock attribute that will be not-uncommon, but it is accessed
externally on mocks when building `method_calls` names and so can't be changed
to a double underscore name.)
If a patch is started using `patch.start` and then not stopped correctly, due
to a bug in the test code, then the unpatching is not done. Using weak
references it would be possible to detect and fix this when the patch object
itself is garbage collected. This is tricky to get right though.
CHANGELOG
=========
2011/05/30 Version 0.7.2
------------------------
* BUGFIX: instances of list subclasses can now be used as mock specs
* BUGFIX: MagicMock equality / inequality protocol methods changed to use the
default equality / inequality. This is done through a `side_effect` on
the mocks used for `__eq__` / `__ne__`
2011/05/06 Version 0.7.1
------------------------
Package fixes contributed by Michael Fladischer. No code changes.
* Include template in package
* Use isolated binaries for the tox tests
* Unset executable bit on docs
* Fix DOS line endings in getting-started.txt
2011/03/05 Version 0.7.0
------------------------
No API changes since 0.7.0 rc1. Many documentation changes including a stylish
new `Sphinx theme `_.
The full set of changes since 0.6.0 are:
* Python 3 compatibility
* Ability to mock magic methods with `Mock` and addition of `MagicMock`
with pre-created magic methods
* Addition of `mocksignature` and `mocksignature` argument to `patch` and
`patch.object`
* Addition of `patch.dict` for changing dictionaries during a test
* Ability to use `patch`, `patch.object` and `patch.dict` as class decorators
* Renamed ``patch_object`` to `patch.object` (``patch_object`` is
deprecated)
* Addition of soft comparisons: `call_args`, `call_args_list` and `method_calls`
now return tuple-like objects which compare equal even when empty args
or kwargs are skipped
* patchers (`patch`, `patch.object` and `patch.dict`) have start and stop
methods
* Addition of `assert_called_once_with` method
* Mocks can now be named (`name` argument to constructor) and the name is used
in the repr
* repr of a mock with a spec includes the class name of the spec
* `assert_called_with` works with `python -OO`
* New `spec_set` keyword argument to `Mock` and `patch`. If used,
attempting to *set* an attribute on a mock not on the spec will raise an
`AttributeError`
* Mocks created with a spec can now pass `isinstance` tests (`__class__`
returns the type of the spec)
* Added docstrings to all objects
* Improved failure message for `Mock.assert_called_with` when the mock
has not been called at all
* Decorated functions / methods have their docstring and `__module__`
preserved on Python 2.4.
* BUGFIX: `mock.patch` now works correctly with certain types of objects that
proxy attribute access, like the django settings object
* BUGFIX: mocks are now copyable (thanks to Ned Batchelder for reporting and
diagnosing this)
* BUGFIX: `spec=True` works with old style classes
* BUGFIX: ``help(mock)`` works now (on the module). Can no longer use ``__bases__``
as a valid sentinel name (thanks to Stephen Emslie for reporting and
diagnosing this)
* BUGFIX: ``side_effect`` now works with ``BaseException`` exceptions like
``KeyboardInterrupt``
* BUGFIX: `reset_mock` caused infinite recursion when a mock is set as its own
return value
* BUGFIX: patching the same object twice now restores the patches correctly
* with statement tests now skipped on Python 2.4
* Tests require unittest2 (or unittest2-py3k) to run
* Tested with `tox `_ on Python 2.4 - 3.2,
jython and pypy (excluding 3.0)
* Added 'build_sphinx' command to setup.py (requires setuptools or distribute)
Thanks to Florian Bauer
* Switched from subversion to mercurial for source code control
* `Konrad Delong `_ added as co-maintainer
2011/02/16 Version 0.7.0 RC 1
-----------------------------
Changes since beta 4:
* Tested with jython, pypy and Python 3.2 and 3.1
* Decorated functions / methods have their docstring and `__module__`
preserved on Python 2.4
* BUGFIX: `mock.patch` now works correctly with certain types of objects that
proxy attribute access, like the django settings object
* BUGFIX: `reset_mock` caused infinite recursion when a mock is set as its own
return value
2010/11/12 Version 0.7.0 beta 4
-------------------------------
* patchers (`patch`, `patch.object` and `patch.dict`) have start and stop
methods
* Addition of `assert_called_once_with` method
* repr of a mock with a spec includes the class name of the spec
* `assert_called_with` works with `python -OO`
* New `spec_set` keyword argument to `Mock` and `patch`. If used,
attempting to *set* an attribute on a mock not on the spec will raise an
`AttributeError`
* Attributes and return value of a `MagicMock` are `MagicMock` objects
* Attempting to set an unsupported magic method now raises an `AttributeError`
* `patch.dict` works as a class decorator
* Switched from subversion to mercurial for source code control
* BUGFIX: mocks are now copyable (thanks to Ned Batchelder for reporting and
diagnosing this)
* BUGFIX: `spec=True` works with old style classes
* BUGFIX: `mocksignature=True` can now patch instance methods via
`patch.object`
2010/09/18 Version 0.7.0 beta 3
-------------------------------
* Using spec with :class:`MagicMock` only pre-creates magic methods in the spec
* Setting a magic method on a mock with a ``spec`` can only be done if the
spec has that method
* Mocks can now be named (`name` argument to constructor) and the name is used
in the repr
* `mocksignature` can now be used with classes (signature based on `__init__`)
and callable objects (signature based on `__call__`)
* Mocks created with a spec can now pass `isinstance` tests (`__class__`
returns the type of the spec)
* Default numeric value for MagicMock is 1 rather than zero (because the
MagicMock bool defaults to True and 0 is False)
* Improved failure message for :meth:`Mock.assert_called_with` when the mock
has not been called at all
* Adding the following to the set of supported magic methods:
- ``__getformat__`` and ``__setformat__``
- pickle methods
- ``__trunc__``, ``__ceil__`` and ``__floor__``
- ``__sizeof__``
* Added 'build_sphinx' command to setup.py (requires setuptools or distribute)
Thanks to Florian Bauer
* with statement tests now skipped on Python 2.4
* Tests require unittest2 to run on Python 2.7
* Improved several docstrings and documentation
2010/06/23 Version 0.7.0 beta 2
-------------------------------
* :func:`patch.dict` works as a context manager as well as a decorator
* ``patch.dict`` takes a string to specify dictionary as well as a dictionary
object. If a string is supplied the name specified is imported
* BUGFIX: ``patch.dict`` restores dictionary even when an exception is raised
2010/06/22 Version 0.7.0 beta 1
-------------------------------
* Addition of :func:`mocksignature`
* Ability to mock magic methods
* Ability to use ``patch`` and ``patch.object`` as class decorators
* Renamed ``patch_object`` to :func:`patch.object` (``patch_object`` is
deprecated)
* Addition of :class:`MagicMock` class with all magic methods pre-created for you
* Python 3 compatibility (tested with 3.2 but should work with 3.0 & 3.1 as
well)
* Addition of :func:`patch.dict` for changing dictionaries during a test
* Addition of ``mocksignature`` argument to ``patch`` and ``patch.object``
* ``help(mock)`` works now (on the module). Can no longer use ``__bases__``
as a valid sentinel name (thanks to Stephen Emslie for reporting and
diagnosing this)
* Addition of soft comparisons: `call_args`, `call_args_list` and `method_calls`
now return tuple-like objects which compare equal even when empty args
or kwargs are skipped
* Added docstrings.
* BUGFIX: ``side_effect`` now works with ``BaseException`` exceptions like
``KeyboardInterrupt``
* BUGFIX: patching the same object twice now restores the patches correctly
* The tests now require `unittest2 `_
to run
* `Konrad Delong `_ added as co-maintainer
2009/08/22 Version 0.6.0
------------------------
* New test layout compatible with test discovery
* Descriptors (static methods / class methods etc) can now be patched and
restored correctly
* Mocks can raise exceptions when called by setting ``side_effect`` to an
exception class or instance
* Mocks that wrap objects will not pass on calls to the underlying object if
an explicit return_value is set
2009/04/17 Version 0.5.0
------------------------
* Made DEFAULT part of the public api.
* Documentation built with Sphinx.
* ``side_effect`` is now called with the same arguments as the mock is called with and
if returns a non-DEFAULT value that is automatically set as the ``mock.return_value``.
* ``wraps`` keyword argument used for wrapping objects (and passing calls through to the wrapped object).
* ``Mock.reset`` renamed to ``Mock.reset_mock``, as reset is a common API name.
* ``patch`` / ``patch_object`` are now context managers and can be used with ``with``.
* A new 'create' keyword argument to patch and patch_object that allows them to patch
(and unpatch) attributes that don't exist. (Potentially unsafe to use - it can allow
you to have tests that pass when they are testing an API that doesn't exist - use at
your own risk!)
* The methods keyword argument to Mock has been removed and merged with spec. The spec
argument can now be a list of methods or an object to take the spec from.
* Nested patches may now be applied in a different order (created mocks passed
in the opposite order). This is actually a bugfix.
* patch and patch_object now take a spec keyword argument. If spec is
passed in as 'True' then the Mock created will take the object it is replacing
as its spec object. If the object being replaced is a class, then the return
value for the mock will also use the class as a spec.
* A Mock created without a spec will not attempt to mock any magic methods / attributes
(they will raise an ``AttributeError`` instead).
2008/10/12 Version 0.4.0
------------------------
* Default return value is now a new mock rather than None
* return_value added as a keyword argument to the constructor
* New method 'assert_called_with'
* Added 'side_effect' attribute / keyword argument called when mock is called
* patch decorator split into two decorators:
- ``patch_object`` which takes an object and an attribute name to patch
(plus optionally a value to patch with which defaults to a mock object)
- ``patch`` which takes a string specifying a target to patch; in the form
'package.module.Class.attribute'. (plus optionally a value to
patch with which defaults to a mock object)
* Can now patch objects with ``None``
* Change to patch for nose compatibility with error reporting in wrapped functions
* Reset no longer clears children / return value etc - it just resets
call count and call args. It also calls reset on all children (and
the return value if it is a mock).
Thanks to Konrad Delong, Kevin Dangoor and others for patches and suggestions.
2007/12/03 Version 0.3.1
-------------------------
``patch`` maintains the name of decorated functions for compatibility with nose
test autodiscovery.
Tests decorated with ``patch`` that use the two argument form (implicit mock
creation) will receive the mock(s) passed in as extra arguments.
Thanks to Kevin Dangoor for these changes.
2007/11/30 Version 0.3.0
-------------------------
Removed ``patch_module``. ``patch`` can now take a string as the first
argument for patching modules.
The third argument to ``patch`` is optional - a mock will be created by
default if it is not passed in.
2007/11/21 Version 0.2.1
-------------------------
Bug fix, allows reuse of functions decorated with ``patch`` and ``patch_module``.
2007/11/20 Version 0.2.0
-------------------------
Added ``spec`` keyword argument for creating ``Mock`` objects from a
specification object.
Added ``patch`` and ``patch_module`` monkey patching decorators.
Added ``sentinel`` for convenient access to unique objects.
Distribution includes unit tests.
2007/11/19 Version 0.1.0
-------------------------
Initial release.